题解 | #在字符串中找出连续最长的数字串#

import java.util.*;
import java.io.*;

public class Main{
    public static void main(String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str;
        while((str = br.readLine()) != null){
            // 输出结果
            System.out.println(longestNum(str));
        }
    }

    
    private static String longestNum(String str){
        String s = str;
      // 创建StringBuilder对象用于保存结果
        StringBuilder sb = new StringBuilder();
        int i = 0,maxLen = 0;
        while(i < str.length()){
            int j = i;
          // 遇到数字开始while循环
            while(i < str.length() && Character.isDigit(str.charAt(i))){
                i++;
            }
            if(i - j == maxLen){
                sb.append(s.substring(j,i));
            }
            if(i - j > maxLen){
                maxLen = i - j;
                sb = new StringBuilder(s.substring(j,i));
            }
            
            i++;
        }
        return sb.append("," + maxLen).toString();
    }
}